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Archive for March, 2009

Does aerobic exercise make you instantly smarter?

March 16th, 2009
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It’s old news that exercise is good for the brain. Dan Peterson of 80percentmental does a nice job of summing up some of the benefits here: increasing blood flow to the brain, making new brain cells, managing glucose. We usually think of that in terms of long-term benefits — stay active to avoid losing your marbles.

That’s why a forthcoming study (now available online) in Medicine & Science in Sports & Exercise caught my attention. Read more…

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Getting older…

March 15th, 2009
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We all are, obviously. These days, whenever I finish a workout that really wipes me out, I wonder whether I’m experiencing age-related decline, or whether I just had a good workout. I wrote about some of the ways we should change our exercise routines as we get older in a Jockology column last fall. But I didn’t have a lot of room to go into detail about the physiology underlying age-related decline — or some of the more subtle factors that affect us. For those who are interested, there’s a fantastic series on exercise and aging currently in progress at The Science of Sport, which is a site run by two sports scientists who trained with the legendary Tim Noakes in South Africa.

Two parts of the series have come out: the first is a general introduction to the topic, while the second goes over the basic physiology related to exercise and aging. A teaser: they begin by presenting the graph showing the best marathon performances for every age from teenagers to nonagenarians.

The Science of Sport's marathon vs. age graph

The Science of Sport's marathon vs. age graph

So that tells us the rate at which our performance will decline with age, right? Wrong — and that’s the whole point of their series:

However, in this case, that predicted decline is based on perhaps 50 DIFFERENT INDIVIDUALS, and you’d be completely incorrect to assume that age causes a decline in performance that is predicted by the equation X. It doesn’t work that way.

Definitely worth a read…

Magic pills

March 13th, 2009

New Jockology out today: it’s the first of a two-part series on popular supplements thought to be ergogenic (performance enhancing). Actually, it could have been a 27-part series — there’s a ton of pills and powders out there that people believe in — but I tried to focus on substances with some legitimate research behind them. This week: antioxidants, omega-3 fatty acids, and creatine (read the column here).

Last summer, researchers at the Salk Institute for Biological Studies in California made a splash by announcing an exercise pill that allowed mice to gain the benefits of vigorous exercise – all without setting a paw on their exercise wheels. That era hasn’t yet arrived for humans, but strolling down the aisle of any drugstore makes it clear that we’re very interested in pills whose claims include faster, higher and stronger.

So, which key ones did I miss? Which ones should I cover in part 2?

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The new, new miracle berry

March 12th, 2009
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At spring training last year, Jeff Blair blogged about Blue Jays first-baseman Lyle Overbay peddling a supplement called MonaVie to his teammates — apparently with great success.

“Had a glass this morning and felt like running to the ballpark,” John McDonald said, winking.

MonaVie relies on the purported antioxidant powers of the açaí berry (that’s acai with assorted diacritical marks, in case it doesn’t display in your browser), joining a long list of antioxidants from obscure plants grown in the farthest corners of the globe. No one doubts that they have antioxidants in them — much like, say, apples. But the other miraculous claims — removing wrinkles, extending life, making shortstops run to work — don’t necessarily follow. Abby Ellin of the New York Times does a nice job checking out the (lack of) research behind the latest supplement craze in today’s paper.

The luxury of walking with poles

March 11th, 2009
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I love the conclusion, in slightly stilted English, of this paper on Nordic walking (a.k.a. walking with poles):

“The work of the upper extremities seems to be a luxury effort for Nordic walkers with a proper technique.”

The study is actually fairly subtle, tracking the pole force and oxygen consumption of walkers on grass, concrete, and rubberized track. Since the walkers had to work much harder on grass even though the pole forces stay the same, the researchers conclude that it’s the legs doing all the work — the arms are just “luxury!”

This is actually something I’ve been wondering about ever since I started seeing hikers zooming up and down mountains using those ski pole thingies. I’ve even been a convert, using them for a 12-day trek in the Rockies. Now they’re ubiquitous, and — German study notwithstanding — I’m curious about their benefits. Perhaps something to look into…

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Bone density, this time for cyclists

March 10th, 2009
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Another new study on bone density, in this month’s Medicine & Science in Sports & Exercise. Since cycling isn’t weight bearing (except when you stand up out of the saddle), it’s often thought to be worse for building bone strength than alternatives like walking. And sure enough, the study I wrote about here found that competitive cyclists had lower spine bone mineral density than controls.

But the new study, from researchers at Manchester Metropolical University in the U.K., concludes that “sprint cyclists and to a lesser extent distance cyclists had greater tibia and radius bone strength surrogates than the controls.”

So, completely contradictory results from two studies measuring slightly different aspects of the same thing. Sounds like we don’t really know what’s going on yet (and don’t even know exactly which questions to ask).

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Eating after exercise, and elite-only hydration

March 10th, 2009
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Check out this study on exercise and weight loss that appeared last month in the journal PLoS One. Sedentary, post-menopausal women exercised for either 72, 136 or 194 minutes per week. All groups lost weight, but the 194-minute group lost significantly less than expected — less than the 136-minute group, in fact. The researchers attribute this to “compensating” factors: in other words, the subjects ate more than their exercise merited.

I wrote about this problem, and some of research addressing it, in this Jockology column. It brings to mind an interesting conversation I had last summer with Lawrence Spriet, a top researcher at the University of Guelph, about the difficulties of providing advice that’s applicable both to hardcore athletes and to the general population. In that case, we were talking about companies like Gatorade, who have to formulate their products to meet the hydration needs of elite athletes working at unbelievable intensities for several hours a day — but who also know that overweight preteens are going to be chugging bottles after going for a brisk walk.

One way Gatorade addresses this is by marketing different levels of product for different needs — they have G2 with fewer calories for less rigorous exercise, for instance. But what I didn’t realize is that the real strong stuff isn’t even available to the public. For college and professional teams, they offer GatorLytes, which are sachets of electrolyte mix that look like the salt or sugar packs you get at a diner, specially formulated so that you can add them to regular Gatorade without messing up the flavour. Unfortunately, you can’t really take that approach with most exercise and nutrition advice: “What, you’re not a professional athlete? In that case, we can’t tell you about this fantastic new exercise.” So we have to be as careful as possible to ensure that the studies we read are really applicable to us, and not just to a tiny subset of the population.

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Mental fatigue and physical performance

March 8th, 2009

There’s an interesting study in this month’s Journal of Applied Physiology about the link between mental fatigue and physical endurance. In a nutshell: “When participants performed a mentally fatiguing task prior to a difficult exercise test, they reached exhaustion more quickly than when they did the same exercise when mentally rested.”

This is a topic I’ve thought a lot about, in part because my occupation is so physically undemanding. I typically spend the day sitting in front of my computer, chatting on the phone, and reading. But if I try to do a hard running workout at the end of a day where I’ve been filing a story on deadline, I STINK! My performance really suffers compared to days when I’ve just been reading or researching. But I don’t get a lot of sympathy from my training partners when I say, “I’m exhausted, I was really typing hard today.”

I had thought it might have something to do with stress hormones, but the researchers (from Bangor University in Wales) suggest another mechanism. Apparently, concentrating hard requires the anterior cingulate cortex region of the brain. Studies have found that rats with a lesion in that area are unable to work as hard for a reward as normal rats — so it may be that our ability to accurately gauge physical effort is put out of whack by too much hard thinking.

This is also another clue that our physical performance limits are almost always mental rather than physical. What we perceive as our bodies reaching their outer limits may, in many cases, just be case of frazzled nerve endings in the anterior cingulate cortex…

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Exercising when you’re sick

March 4th, 2009
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Blah. I have a sore throat, a bit of congestion, and I’ve been feeling crappy for a couple of days. So should I exercise or not? Nobody really knows. A few months ago, Gina Kolata wrote an interesting article in the New York Times on this question. A couple of studies done a decade ago suggest that a head cold won’t hurt your capacity to exercise (though you may feel more tired), and exercise won’t speed up or slow down your recovery (though it may make you feel better). Other than that, we’re all just guessing.

Me, I took yesterday off and hoped that would be enough. Then I went for a short jog this morning, but cut it short when I felt worse than I expected. Cliche though it is, listening to your body is probably the best we can do for now. If you start feeling better as you get into it, that’s great; if you feel worse, cut your losses.

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Running and bone density: more info

March 1st, 2009
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Wow, research moves pretty quickly. Just a few hours after posting about the lack of good evidence that running helps bone density…presto! I get a press release about an article by University of Missouri researchers in the current issue of the Journal of Strength and Conditioning Research about how great running is for bone density. You can read the press release here:

In the study, the researchers determined the effects of long-term running, cycling, and resistance training on whole-body and regional BMD [bone mineral density], taking into account the effects of body weight and composition, in men ages 19 to 45. After adjusting for differences in lean body mass, the researchers found that runners had greater spine BMD than cyclists.

This still doesn’t tell us explicitly about how activities like elliptical training, which are weight-bearing but not high-impact, affect bone density. The University of Missouri researchers seem pretty convinced that the jarring action of running (or jumping around by playing basketball, for example) helps bone density. The question is, how much?

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